Pressure feeding attachment for tapping machines



Nov. 2, 1943. G E, MlTH 2,333,276

PRESSURE FEEDING ATTACHMENT FOR TAPPING MACHINES Filed July 7, 1942 3 Sheets-Sheet l Inventor G. E. SMITH 2,333,276

PRESSURE FEEDING ATTACHMENT FOR TAPPING MACHINES Nov. 2, 1943.

Filed July 7, .1942 3 Sheets-Sheet 2 Iuventor Gerald ETSmtZk y firm J i Attorneys New. 2, 1943. G. E. SMITH 2,333,276

PRESSURE FEEDING ATTACHMENT FOR TAPPING MACHINES Filed July 7, 1942 3 sheets sheet 5 Gem/3d 35m? v 4a 5 r I B).

Patented Nov. 2, 1943 PRESSURE FEEDING ATTACHMENT FOR TAPPING MACHINES Gerald E. Smith, Lower Salem, Ohio Application July 7, 1942, Serial No. 450,073

7 Claims.

The present invention relates to tapping machines and has for its primary object to provide a compressed air feed attachment for controlling the feeding of the tap under uniform pressure and feed in relation to the work whereby to eliminate the objectionable features in a machine of this character employing manual pressure for applying the tap during the operation of the machine.

A further object of the invention is to provide an attachment of this character of simple and practical construction, which is efficient and reliable in performance, relatively inexpensive to manufacture and install in operative position upon a conventional form of tap machine, and which is otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a side elevational View.

Figure 2 is a front elevational view.

Figure 3 is a vertical sectional view through the air cylinder.

Figure 4 is a sectional view through the foot pedal control valve.

Figure 5 is a side elevational view showing the opposite side from that shown in Figure 1.

Figure 6 is a fragmentary top plan view, and

Figure 7 is a sectional view taken substantially on a line 1-1 of Figure 5.

Referring now to the drawings in detail, wherein for the purpose of illustration I have disclosed a preferred embodiment of the invention, the numeral 5 designates the base of a conventional form of drill press from which rises a tubular standard 6 on which is mounted a bracket 1 which carries a motor 8 at one side while in the other side is suitably journaled a shaft 9, the shaft being driven by means of a stepped pulley l0 operatively connected to the shaft, while a stepped pulley I l is keyed to the motor shaft, the pulleys being operatively connected by means of a belt [2.

The shaft 9 carries a tapping attachment l3 secured in a chuck [4 for holding a tap l5. A table [6 is adjustably carried upon the standard and is adapted to hold the work to be tapped in a manner well known in the art.

The shaft 9 includes spaced flanges l1 and I8 between which a yoke I9 is positioned, the yoke being pivoted as at 20 on the bracket 1, and the other end of the yoke is connected to the upper end of a vertically disposed rod 2|, the lower end of the rod being slidably mounted in the upper end of a tube 22 which is pivotally attached at its lower end to a foot treadle 23 by means of the pin 24. A collar 25. carried by the tube 22 is adjustably secured to the rod 2| by a set screw 25' to actuate the yoke IQ for lowering the tap into work-engaging position. A spring 23' attached to the treadle returns the tap to its normal position. The foregoing operating mechanism for the tap is of conventional construction and is employed when foot pressure is desired for operating the tap into its work-engaging position. I

A bracket 26 is attached to the standard 6 by means of U-bolts 21, the bracket supporting a cylinder 28 thereon in an upright position, the cylinder having a piston 29 working therein and to which a piston rod 31! is attached by means of a wrist pin 3!. The rod 30 is of tubular construction and extends upwardly in substantially spaced parallelism with respect tothe tube 22 and slidably positioned in the upper end of the piston rod 36 is a rod 32 which acts as aguide for the piston rod, the upper end of" the rod 32 being attached to the bracket 1 by means of a brace structure 33. The upper end of the piston rod 30 is connected to the rod 2| by means of a split clamp 34 secured to the piston rod, the clamp having a forked end 35 engaged under a collar 36 adjustably secured to the rod 2| by means of a set screw 31. Accordingly, an upward movement of the piston 29 and rod 30 will cause a similar movement to the rod 2! whereby to lower the tap.

An air feed pipe 38 extends upwardly through the bracket 26 into the lower end of the cylinder 28, the air feed pipe having a rotary valve 39 therein which includes a casing 40 having a discharge port 41, the pipe 38 communicating with the casing equidistantly between the discharge port 4| and an air intake port 42. The valve 39 is formed with radially extending passages 43 and 44 communicating at their inner ends and adapted to connect the pipe 38 with the port 42 when the valve is in one position and adapted to connect the pipe 38 with the port 4| when the valve is in another position. A compressed air supply pipe 45 is connected to the port 42 leading to a suitable source of compressed air supply and the pipe 45 has a valve 46 therein together with a pressure regulator 41 of conventional construction so that a uniform pressure may be admitted to the cylinder 28, when desired.

A shaft 48 is provided for the valve 39 and projects outwardly through one side of the casing 40 and to which is secured a foot pedal 49 by means of a U-bolt 50.

Accordingly, upon a rocking movement of the pedal 49 by the foot of the operator, the valve 39 will be moved into its opened and closed positions for admitting air under pressure to the cylinder 28 or exhausting the air therefrom, when desired.

An adjustable relief valve 5| is connected to the discharge port 4| to control escape of air from the cylinder in order to synchronize the movement of the piston with the backing out of the tap from the work so as to prevent mutilation of the threads by too great a lifting force on the tap. I

It is believed the details of construction, operation and advantages of the device will be readily understood from the foregoing without further detailed explanation.

Having thus described the invention what I claim is:

1. In a tapping machine having a manually operated rod for moving thet'a'p into and out of engagement with the work, a fluid pressure actuate'd rod, and means eperatively connecting the second-named rod to the first-named rod for actuating the tap by either of said rods, one

fluid pressure operating means for the second 'rod, said first-married rod being manually operable independently of the second rod and spring means for moving the tap out of work-engaging position.

3. In a tap-ping machine, a rod operative-1y connected to the tap for moving the latter into and out of engagement with the work, a cylinder, a piston working therein, a rod connected to the piston, means for subjecting the piston to fluid pressure, means connecting the rods for actuation of the tap into work-engaging position upon a movement of the 'secondnamed rod in one direction, said first-named rod being manually operable independently of the second rod, and spring means for moving the tap out 'of work-engaging position.

4. In a tapping machine, a rod operatively connected to the tap for moving the latter into and out of engagement with the work, a cylinder, a piston working therein, a tubular rod connected to the piston and disposed in parallel relation to the first-named rod, a guide rod for the tubular rod, means connecting the first and second rods for simultaneous actuation upon a movement of the tubular rod in one direction, said first-named rod being free for independent movement, and means tor subjecting the piston to fluid pressure.

5. In a tapping machine, a rod operatively connected to the tap for moving the latter in- "to and out of engagement with the work, a cylfinder, a piston working therein, a tubular rod connected to the piston and disposed in parallel relation to the first-named rod, a guide rod for the tubular rod, means connecting the first and second rods for simultaneous actuation upon a movement of the tubular rod in one direction, said first-named rod being free for, independent movement, a fluid pressure supply pipe connected to the cylinder, a control valve in said pipe, and a foot pedal for said valve.

6; In a tapping machine, a .rod operatively connected to the tap for moving the latter into and out of engagement with the work, a cylinder, 2. piston working tnereima md' connected to the piston, means for subjecting the piston to fluid pressure, means connecting the rods for actuation of the tap into work-engaging position, spring means for moving the tap out or wormengaging position, said first-named rod being free for independent movement, and an adjustable relief valve tor the cylinder to regulate exhaust of iluld pressure therefrom in accordance with the Withdramng movement of the tap.

7. In a tapping machine, a rod operetlvely connected to the tap for moving the latter into and out of engagement with the work, a cylinder, a piston working therein, a tubular rod com nected to the piston and disposed in parallel relation to the ilrstnamed rod, a guide rod 'for the tubular rod, means connecting the and seconds rods for simultaneous actuation upon a movement of the tubular rod in one-direction, said first named rod being free for independent movement,a fluid pressure supply pipe connected to the cylinder, arotary control valve in said pipe, and a rockable 'foot'pedal connected to said valve andarranged for opening and closing the valve upon opposite rocking movement of the pedal.

GERALD E. SMITH. 

